fix: validation of 'freqs' in component modelers

Author: dmarek-flex

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improved the robustness of batch jobs. The batch state, including all `task_ids`, is now saved to `batch.hdf5` immediately after upload. This fixes an issue where an interrupted batch (e.g., due to a kernel crash or network loss) would be unrecoverable.
 - Fixed warning for running symmetric adjoint simulations by port to not trigger when there is a single port.
 - Bug in `CoaxialLumpedPort` where source injection is off when the `normal_axis` is not `z`.
+- Validation of `freqs` in the `ComponentModeler` and `TerminalComponentModeler`.
 
 ## [2.9.0] - 2025-08-04
 

tests/test_plugins/smatrix/test_terminal_component_modeler.py

@@ -87,6 +87,28 @@ def test_validate_no_sources(tmp_path):
         _ = modeler.copy(update={"simulation": sim_w_source})
 
 
+def test_validate_freqs():
+    """Ensure the 'freqs' array is strictly increasing and length of at least 2."""
+    modeler = make_component_modeler(planar_pec=False)
+    freqs = np.array([1.0])
+    with pytest.raises(pd.ValidationError):
+        _ = modeler.updated_copy(freqs=freqs)
+    freqs = np.array([-1.0, 5])
+    with pytest.raises(pd.ValidationError):
+        _ = modeler.updated_copy(freqs=freqs)
+    freqs = np.array([1, 2, 1.9])
+    with pytest.raises(pd.ValidationError):
+        _ = modeler.updated_copy(freqs=freqs)
+
+    # Test case with non-unique value
+    f_min, f_max = (0.5e9, 1.5e9)
+    f0 = (f_min + f_max) / 2
+    f_target = 1.35e9
+    freqs = np.sort(np.append(np.linspace(f_min, f_max, 21), f_target))
+    with pytest.raises(pd.ValidationError):
+        _ = modeler.updated_copy(freqs=freqs)
+
+
 def test_validate_3D_sim(tmp_path):
     modeler = make_component_modeler(planar_pec=False, path_dir=str(tmp_path))
     sim = td.Simulation(

tidy3d/plugins/smatrix/component_modelers/base.py

@@ -147,7 +147,26 @@ def _warn_deprecation_2_10(cls, values):
     def _sim_has_no_sources(cls, val):
         """Make sure simulation has no sources as they interfere with tool."""
         if len(val.sources) > 0:
-            raise SetupError("'AbstractComponentModeler.simulation' must not have any sources.")
+            raise SetupError(f"'{cls.__name__}.simulation' must not have any sources.")
+        return val
+
+    @pd.validator("freqs", always=True)
+    def _validate_freqs(cls, val):
+        """The array of frequencies must be sorted, unique and non-negative."""
+        if len(val) < 2:
+            raise SetupError(f"You must supply at least 2 entries for '{cls.__name__}.freqs'.")
+        np_val = np.array(val)
+        if not np.all(np_val >= 0):
+            raise SetupError(f"'{cls.__name__}.freqs' must be an array of non-negative numbers.")
+        # Ensure freqs is sorted
+        diff = np.diff(np_val)
+        if not np.all(diff > 0):
+            violations = np.where(diff <= 0)[0] + 1
+            raise SetupError(
+                f"'{cls.__name__}.freqs' must be strictly increasing (unique values sorted "
+                "in ascending order). "
+                f"The entries at the following indices violated this requirement: {violations}."
+            )
         return val
 
     @pd.validator("ports", always=True)